An ultrasound diagnostic apparatus sends an ultrasonic wave to the inside of a diagnosing object by an ultrasound probe, receives a reflected echo signal which corresponds to a structure of a biological tissue from the inside of the diagnosing object, and forms a multi-planar reconstruction (B-mode) image, e.g., an ultrasonic multi-planar reconstruction (B-mode) image (B-mode image), or the like, to be displayed for a diagnosis.
In order to collect three-dimensional ultrasonic data, in the typical technique, three-dimensional data obtained by scanning a probe automatically or manually in a short axis direction is subject to coordinate conversion, thereafter ultrasonic image data is reconfigured in a visual line direction, and a three-dimensional image is created, thereby a surface of an object is observed.
Also, the recent typical technique is a technique called real-time 3D or 4D, in which signal processing described above is performed in real time, and a moving three-dimensional image is displayed.
These three-dimensional images are excellent at the delineation ability of a surface shape, and are useful in diagnosis of a disease about a fissure on the skin (a labial fissure, a palatal fissure or the like), which is conventionally difficult to diagnose from an ultrasound multi-planar reconstruction (B-mode) image displaying a single cross section region.
However, an ultrasound image has many artifacts unique to ultrasonic waves, such as speckle noises. Therefore, the image quality is improved by a smoothing process, but the smoothing process, as an opposite effect, makes a border continuous so that the fissure on the skin is continuously displayed.
As a method for solving this problem, of image processing apparatuses capable of a three-dimensional image display, there is an image processing apparatus that conducts both of the structure grasp and surface shape extraction for an inspection object and that can obtain a composition three-dimensional image with a good image quality (see Patent Literature 1, for example).